Continuous production of organo-aluminum compound

ABSTRACT

IN A PROCESS FOR SYNTHESIZING AN ALKYLALUMINUM COMPOUND BY REACTING ALUMINUM, HYDROGEN AND AN OLEFIN, OR ALUMINUM AND HYDROGEN IN THE PRESENCE OF TRIALKYLALUMINUM AS A CATALYST, THE ALKYLALUMINUM COMPOUND IS ECONOMICALLY PRODUCED IN A CONTINOUS MANNER BY INTRODUCING A TRIALKYLALUMINUM COMPOUND, HYDROGEN OR AN OLEFIN TO THE LOWER PART OF A COLUMN-TYPE REACTOR PACKED WITH ALUMINUM CUT PIECES HAVING AN APPARENT SPECIFIC SURFACE AREA OF NOT MORE THAN 60 CM2/G. FOR EFFECTING REACTION AND WITHDRAWING THE FORMED ALKYLALUMINUM COMPOUND FROM THE UPPER PART OF THE REACTOR.

March 28, 1972 ucm |cH|K| EI'AL 3,652,621

CONTINUOUS PRODUCTION OF ORGANOALUMINUM COMPOUND Filed May 21, 1970Eiichi ICHIKI Kazuo IIDA Aturo MATUI INVENTOR BY STEVENS, DAVIS, MILLER& MOSIIER ATTORNEY United States Patent O 3,652,621 CONTINUOUSPRODUCTION OF ORGANO- ALUMINUM COMPOUND Eiichi Ichiki, Kazuo Iida, andAturo Matui, Niihama,

Japan, assignors to Sumitomo Chemical Company, Ltd., Osaka, JapanContinuation-impart of application Ser. No. 680,321,

Nov. 3, 1967. This application May 21, 1970, Ser.

Int. Cl. C07f 5/06 U.S. Cl. 260448 A 7 Claims ABSTRACT OF THE DISCLOSUREIn a process for synthesizing an alkylaluminum compound by reactingaluminum, hydrogen and an olefin, or aluminum and hydrogen in thepresence of trialkylaluminum as a catalyst, the alkylaluminum compoundis economically produced in a continuous manner by introducing atrialkylaluminum compound, hydrogen or an olefin to the lower part of acolumn-type reactor packed with aluminum cut pieces having an apparentspecific surface area of not more than 60 cm. g. for effecting reactionand withdrawing the formed alkylaluminum compound from the upper part ofthe reactor.

CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-partapplication of the copending application \Ser. No. 680,321, filed onNov. 3, 1967 and now abandoned.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to a process for producing continuously a dialkylaluminumhydride or a trialkylaluminum, and more particularly to an improvementin a process for producing continuously a dialkylaluminum hydride or atrialkylaluminum by reacting aluminum and hydrogen, or aluminum,hydrogen and an olefin in the presence of a trialkylaluminum as acatalyst.

DESCRIPTION OF THE PRIOR ART As is well known, K. Ziegler et al. found aprocess for producing a dialkylaluminum hydride or a trialkylaluminum byreacting aluminum and hydrogen, or aluminum, hydrogen and an olefin inthe presence of a trialkylaluminum as a catalyst [for example, seeAngew. Chem. vol. 67, No. 16, page 424 (1955)].

-A process for continuously synthesizing such alkylaluminum compound isknown from US. Pat. No. 3,000,919. According to said process, aluminumactivated with a halogen gas or a halogen compound is filled in acolumntype reactor provided with a perforated plate at the bottom of thereactor, and a trialkylaluminum as a catalyst, hydrogen and an olefinare introduced into the upper part of the reactor for efiecting thereaction. The formed alkylaluminum compounds and aluminum made finer bythe reaction are withdrawn from the lower part of the reactor, and thealkylaluminum is obtained by separating it from the fine aluminum.However, in carrying out said process, the aluminum made finer in thecourse of the reaction clogs the perforations of the perforated plate,and the fiow rate of efiluent reaction product solution is liable tofluctuate. Thus, no stable operation can 'be expected.

Furthermore, according to said process, a large amount of aluminum madefiner by the reaction is contained in the product trialkylaluminum,because the trialkylaluminum as the catalyst and an olefin are allowedto pass in the direction of the gravity. Consequently, clogging is3,652,621 Patented Mar. 28, 1972 liable to take place in the pipes or atvalves in the lines for withdrawing the product trialkylaluminum orrecycling the alkylaluminum compounds, and a continuous, stableoperation becomes difiicult for a prolonged period of time. Furthermore,a large amount of the raw material aluminum is liable to take place. Asthe relevant reaction is exothermic, side reaction that converts theolefin to parafiin will take place to a considerable degree, unless theheat of reaction is effectively removed from the reactor. According tosaid process the aluminum is not sufficiently dipped with reaction mediasuch a trialkylaluminum and olefin, but reaction media only attaches tothe surface of the aluminum. Thus, the heat of reaction cannot beeffectively removed, and a chance for the side reaction is considerablyincreased. These are the disadvantages of the prior art process.

SUMMARY OF THE INVENTION An object of the present invention is toprovide an improved process for continuously producing dialkylaluminumhydride or trialkylaluminum. That is to say, the object of the presentinvention is to provide a process for economically producing analkylaluminum compound in a continuous manner, which comprises fillingaluminum cut pieces having an apparent specific surface area of not morethan 60 cm. g. as a raw material in a column-type reactor, introducing atrialkylaluminum as a catalyst, hydrogen and, if necessary an olefininto the reactor from the lower part thereof for effecting reaction, andwith drawing the resulting alkylaluminum compound from the upper part ofthe reactor.

The term apparent specific surface area referred to herein is defined tobe a surface area per weight, where the surface area is calculated, forexample, from a length, a width and a thickness for a plate-shaped pieceor from a diameter for a spherical piece.

The term aluminum cut piece referred to herein is defined to an aluminumcut piece prepared by a lathe, a milling machine, a drilling machine, ashaper, a slotter or the like and is distinguished from a block orpowders prepared by casting or atomizing.

BRIEF DESCRIPTION OF THE DRAWING The accompanying drawing shows acolumn-type reactor used in the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will beexplained in detail, referring to the accompanying drawing, especiallyin view of the reacting materials used in carrying out the presentinvention, flow of the reacting materials and reacting conditions.

In the drawing, a column-type reactor 10 is provided with an aluminumfeeding device 11 at the .top of the reactor, an outlet line 5 forWithdrawing formed alkylaluminum compound, an inlet line 2 forintroducing trialkylaluminum as a catalyst at the lower part of thereactor, an inlet line 3 for hydrogen and an inlet line 4 for olefin. Itis not necessary to use the inlet line 4 for olefin, when adialkylaluminum hydride is to be prepared.

:In order to prevent the product alkylaluminum compound fromcontamination with aluminum made finer by the reaction, it is desirableto use a column-type reactor whose upper section has a larger innerdiameter than that of the aluminum-packed layer section 8, or acolumntype reactor having a wire-net or a perforated plate at theposition to which the outlet line 5 for withdrawing the productalkylaluminum compound is connected. Usually, a reactor having a ratioof height to inner diameter of not less than 3, particularly preferablymore than 10, is used. The reaction can be carried out in a singlereactor or a plurality of reactors connected in series.

Aluminum cut pieces having an apparent specific surface area of not morethan 60 cm. /g., particularly preferably 50 to cm. /g., are used in thepresent invention. The aluminum cut pieces are prepared by a lathe, amilling machine, a drilling machine, a shaper, a slotter or the like.The present inventors have found that the thus prepared aluminum cutpieces have a reaction activity per apparent specific surface area atleast two times as high as that of the aluminum pieces prepared bycasting or atomizing.

A process for synthesizing an alkylaluminum compound very advantageouslyhas been made possible by a combination of said finding with otherconditions.

When said aluminum cut pieces having larger sizes are used in thereaction, the amount of the aluminum fine particle which is contained inthe formed alkylaluminum compound is almost negligible. Thus, thepresent invention is very economical.

The raw material aluminum cut pieces 1 are intermittently orcontinuously introduced into the upper part of the reactor through thefeeding device 11, and led to the packed layer 8 as shown in thedrawing. Thus, there take place no cloggings in the pumps or valves asseen when the conventional raw material aluminum powders are supplied tothe reactor in a slurry state, and consequently there is no trouble inthe continuous operation.

The raw material aluminum cut pieces can be supplied to the reactor,after activated in advance, or can be activated in the reactor. As anactivating agent, for example, metal of the Group Ia, Hz: or III of thePeriodic Table or their compounds can be used. The aluminum cut piecescan be also used even in a non-activated state, but in such a case, thestart of reaction is retarded.

As the trialkylaluminum to be introduced into the reactor as thecatalyst, such trialkylaluminum having an alkyl group having 2 to 20carbon atoms, as triethylaluminum, tripropylaluminum,tri-n-butylaluminum, triisobutylaluminum, tripentylaluminum,trihexylaluminum, tri-Z-ethylhexylaluminum, etc. can be used. Thesetrialkylaluminums can be used alone or in a mixture thereof.Furthermore, these trialkylaluminums can be used in a mixture with suchan organic solvent as hexane, heptane, or the like. However, it is notalways necessary to introduce into the reactor the trialkylaluminum inthe form of trialkylaluminum as the catalyst. That is, it can beintroduced into the reactor in the forms of dialkylaluminum hydride andan olefin and a trialkylaluminum may be formed in the reactor. Thetrialkylaluminum is introduced into the reactor from the line 2connected to the lower part of the reactor. A portion of thetrialkylaluminum, the olefin and/or the organic solvent can beintroduced to the middle part of the reactor divisionally to effectivelyremove the heat of reaction.

When the trialkylaluminum is introduced into the reactor from the lowerpart thereof in this manner, the inside of the reactor is completelyfilled with a reacting solution and the reaction is carried out in sucha state. Consequently, the heat of reaction can be effectively removedin the present invention, as compared with the case where the reactionis carried out in such a state that the aluminum surfaces are wet withthe reacting solution, as disclosed in US. Pat. No. 3,000,919. Thus, theoperation can be carried out smoothly in the present invention. Thismeans that a chance for such a side reaction as given below can bereduced to a considerable degree:

wherein R represents an alkyl group.

The hydrogen gas is introduced into the reactor from the line 3connected to the lower part of the reactor.

The introduction of the hydrogen gas into the reactor from the lowerpart thereof can bring about such an advantage that the contact ofaluminum and trialkylaluminum with hydrogen can be carried outefliciently. The hydrogen pressure in the reactor is maintained at 40300kg./cm. particularly 50-l50 kg./cm. The temperature of the reactor ismaintained at 200 C., particularly 1l0160 C. The formed alkylaluminumcompound is withdrawn from the upper part of the reactor through theline 5. Thus, contamination of the formed alkylaluminum compound with alarge amount of the aluminum made finer by the reaction, which isobserved when the formed alkylaluminum compound is tanken out from thereactor in a direction of the gravity, can be prevented. The etfiuentsolution consists mainly of unreacted trialkylaluminum, formeddialkylaluminum hydride and very small amounts of fine aluminum residue,hydrocarbon and hydrogen. The etlluent solution can be used in a certainapplication after it has been degasified and separated from the finealuminum residue. However, the efiluent solution is generally allowed tocome in contact with a suitable olefin in an olefin addition reactor(not shown in the drawing) provided in the course of the line 5, toconvert the formed dialkylaluminum hydride to trialkylaluminum, and thenwithdrawn from the line 7 as a product, or can be reused as a rawmaterial for the reaction by leading it through the lines 6 and 2 to thereactor 10.

In the foregoing, a process for synthesizing a di-alkylaluminum hydridehas been explained, but it is readily comprehensible that the presentprocess can be also applied to a synthesis of a trialkylaluminum in onestage. That is, in a process for synthesizing a trialkylaluminum in onestage, aluminum, a trialkylaluminum, hydrogen and an olefin are used asraw materials and treated under the reacting conditions similar to thosefor synthesizing said dialkylaluminum hydride.

Olefins having 2 to 20 carbon atoms, such as ethylene, propylene,isobutylene, butene-l, 2-ethylhexene-1, 3- methylhexene-l, Z-ethyl 4methylpentene-l, butene-Z, octene-2, or the like can be used alone or ina mixture as the raw material olefin. Furthermore, these olefins can beused in a mixture with such an inert solvent as parafiins, etc.

The olefin is introduced into the reactor from the line 4 connected tothe lower part of the reactor.

A molar ratio of the olefin to the trialkylaluminum as a catalyst, whichare introduced in the one-stage synthesis of the trialkylaluminum, is avery important condition for reducing the proportion for occurrence of aside reaction, that is, hydrogenation of the olefin and economicallysynthesizing trialkylaluminum. That is to say, if the molar ratio issmaller, the proportion for the occurrence of the side reaction isincreased, resulting in the loss of olefin. On the other hand, if themolar ratio is too large, the amount of recycle olefin is undulyincreased and the process becomes uneconomical. Thus, the molar ratio ofthe olefin to the trialkylaluminum usually used in the present inventionis 0.5 to 5 0, particularly preferably 1 to 20.

The formed trialkylaluminum is withdrawn from the upper part of thereactor through the line 5. The thus obtained trialkylaluminum isrecycled to the reactor as the catalyst through the lines 6 and 2 orwithdrawn as a product through the line 7, as it is, or after it hasbeen degasified or separated from the hydrocarbon and a very smallamount of fine aluminum residue.

catalyst, hydro-gen and olefin and the withdrawing posi-.

tion of the formed alkylaluminum compound. For example, the solution ispassed through the reactor from the bottom upwards in the presentinvention, and thus clogging of the perforated plate with the aluminummade finer by the reaction and the resulting fluctuation in the liquidflow or in reaction or decrease in the efliciency of the reaction, asseen in US. Pat. No. 3,000,919, are not brought about.

Further, in the present invention, the formed alkylaluminum compound istaken out of the reactor as an ascending stream, and thus the amount ofaluminum, which has been made finer by the reaction and contained in theproduct alkylaluminum compound, can be made very small. That is,separation of the unreacted aluminum residue from the formedalkylaluminum compound withdrawn from the reactor can be made readily,and no cloggings take place at all in the pipes and valves.

Furthermore, in the present invention, the reaction is carried out in aliquid phase, and the removal of the heat of reaction can be carried outreadily. Thus, the occurrence of the side reaction can be prevented to aconsiderably degree.

Still furthermore, in the present invention the reaction is not carriedout in such a state that aluminum is suspended in a reacting solution,and thus the amount of aluminum in the reactor can be considerablyincreased. Consequently, the volume efliciency is increased, and theapparatus cost can be remarkably decreased. These are the advantages ofthe present invention. According to the present invention analkylaluminum compound can be very economically produced in a continuousmanner.

Now, the present invention will be explained in detail, referring toexamples, to which the present invention should not be interpreted aslimitative.

The present invention can be varied within the scope and spirit of thepresent invention EXAMPLE 1 35 kilograms of lathe waste aluminum havingan apparent specific surface area of -40 cm. g. were packed in acolumn-type reactor having a height of 3 m. and a capacity of 45 1., anddiisobutylaluminum hydride containing 1% sodium ethoxide was chargedtherein to such an extent that the aluminum was immersed therein.Activation was carried out at a temperature of 140 C. under a pressureof 50 kg./cm. gage for three hours. Then, hydrogen gas was fed to thelower part of the reactor from the line 3 and compressed to 100 kg./cm.gage. 1.1 kg./hr. of triisobutylaluminum as a catalyst was introduced tothe lower part of the reactor from the line 2 and 3 kg./ hr. of a butenegas mixture containing 70% by mole of isobutylene was introduced to thelower part of the reactor from the line 4, to efifect reaction, whilekeeping the reactor at 140 C. under 100 kg./cm. gage. At every 70 hours,13 kg. of the same aluminum activated in advance as above was suppliedto the aluminum-packed layer 8 through the aluminum-feeding device 11.After the reaction was brought into a stationary state, 2.4 kg./hr. ofalkyl-aluminum compounds consisting of 80% by weight oftriisobutylaluminum and by weight of diisobutylaluminum hydride wasobtained from the upper part of the reactor through the line 5. Thereaction was carried out without any trouble, and no aluminum residuemade finer by the reaction was observed in the formed alkylaluminumcompounds almost at all.

EXAMPLE 2 kilograms of the same aluminum as used in Example 1 was packedin the same reactor as used in Example 1, and triisobutylaluminumcontaining 1% potassium tert.- butoxide was fed thereto to such anextent that the aluminum was dipped therein. Activation was carried outat a 6 temperature of 140 C. under a pressure of 50 kg./cm. gage. Then,hydrogen gas was introduced into the lower part of the reactor from theline 3, and compressed to kg./cm. gage. 7.2 kg./hr. oftriisobutylaluminum as a catalyst was introduced to the lower part ofthe reactor through the line 2, while keeping the reactor at 140 C.

under 100 kg/cm? gage. At every 120 hours, 13 kg. of

the same aluminum activated in advance as above was supplied to thealuminum packed layer from the feeding device 11. After the reaction wasbrought into a stationary state, 70 kg./hr. of alkylaluminum compoundsconsisting of 70.5% by weight of triisobutylaluminum and 29.5% by weightof diisobutylaluminum hydride was obtained from the upper part of thereactor through the line 5. The reaction was continuously carried outwithout any trouble, and no aluminum residue made finer by the reactionwas observed in the formed alkylaluminum compounds almost at all.

What is claimed is:

1. In a process for synthesizing a dialkylaluminum hydride, by reactingaluminum and hydrogen in the presence of a trialkylaluminum as acatalyst, an improved process for continuously synthesizing adialkyaluminum hydride, which comprises introducing a trialkylaluminumas a catalyst and hydrogen to the lower part of a columntype reactorpacked with aluminum cut pieces having an apparent specific surface areaof not more than 60 cm. /g., eflecting reaction at reaction temperatureof 100200 C. under a reaction pressure of 40-300 kg./cm. and withdrawingthe thus formed dialkylaluminum hydride from the upper part of thereactor.

2. A process according to claim 1, wherein the aluminum cut pieces havean apparent specific surface area of 5010 cm. g.

3. A process according to claim 1, wherein the reaction temperature is-160 C. and the reaction pressure is 50-150 gk./cm.

4. In a process for synthesizing a trialkylaluminum by reacting aluminumhydrogen and an olefin in the presence of a trialkylaluminum as acatalyst, an improved process for continuously synthesizing atrialklaluminum, which comprises introducing a trialkylaluminum as acatalyst, hydrogen and an olefin to the lower part of a columntypereactor packed with aluminum cut pieces having an apparent specificsurface area of not more than 60 cm. g. in a molar ratio of the olefinsof the trialkylaluminum of 05-50, effecting reaction at reactiontemperature of 100- 200 C. under a reaction temperature of 40-300kg./cm. and withdrawing the thus formed trialkylaluminum from the upperpart of the reactor. 1

5. A process according to claim 4, wherein the aluminum cut pieces havean apparent specific surface area of 50-10 cmF/g.

6. A process according to claim 4, wherein the reaction temperature is110-160 C. and the reaction temperature is 50-150 gk./cm.

7. A process according to claim 4, wherein the olefin is at least onemember selected from the group consisting of ethylene, propylene,isobutylene, butene-l, 2-ethylhexene-l, 3-methylhexene-1, 2-methyl 4methylpentene-l, butene-2 and octene-2.

References Cited UNITED STATES PATENTS 9/1961 Hetroff et a1 260-448 ATOBIAS E. LEVOW, Primary Examiner H. M. S. SNEED, Assistant ExaminerUNITED STATES PATENT OFFICE CERTEFICATE @F CORRECTIUN Dated March 28,1972 Patent No. 3 652. 621

InVent I-( EIICHI ICHIKI et al.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Please insert' the following missing claim for priority:

-Japanese No. 75103/66 of November 14, 1966-- Signed and sealed this 3rdday of October 1972.

(SEAL) Attest:

ROBERT GQTTSCHALK EDWARD M.FL.ETCHER,JR. Attestlng Officer- Commissionerof Patents USCOMM-DC 80376-P69 u.sv GOVERNMENT wnnmuc OFFICE 1959o-:es-aa4 FORM PC4050 (10-69)

